JPH09184482A - Arrangement of evacuation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the evacuation time, to enhance the finally achieving pressure and the cleanliness and to simplify the arrangement of an evacuation device by simultaneously driving a plurality of pumps having different discharge characteristics so as to carry out evacuation. SOLUTION: A high vacuum range pump 4, a middle vacuum range pump 3, a low vacuum range pump 2 and a dry pump 9 are simultaneously driven so as to evacuate a processing chamber 1 through first to third branch exhaust pipes 5, 6, 7 branching from a main exhaust pipe 8 at a lateral surface of the processing chamber 1. The low vacuum range pump 2 is mainly effective in the low vacuum range, and the other two pumps have auxiliary roles. In the middle vacuum range, the middle vacuum range pump 3 is mainly effective while the other two pumps have auxiliary roles. Further, in the high vacuum range, the high vacuum range pump is effective while the other two pumps have auxiliary roles. Since at least one of the three kinds of pumps is effective in each of the three vacuum ranges, it is possible to obtain a sufficient finally achieving pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum exhaust device for various devices including a vacuum chamber such as a semiconductor manufacturing device.

[0002]

2. Description of the Related Art A high degree of vacuum and a high degree of cleanliness are required in a semiconductor manufacturing process, and an improvement in throughput is required by shortening an evacuation time for achieving a high degree of vacuum.

The structure of a conventional vacuum exhaust device will be described below. Vacuum pumping in conventional semiconductor manufacturing equipment is a dry pump (DRP) combined with a mechanical booster pump (MBP) that has high pumping performance in a low vacuum range, or a dry pump (DRP) in a high vacuum range. The turbo molecular pump (TMP) having a high exhaust performance was combined, and the two configurations were used.

[0004]

However, in addition to the above-mentioned dry pump (DRP), a mechanical booster pump (M
The vacuum exhaust system combined with BP) has a high exhaust speed in the low vacuum region, but the exhaust performance deteriorates as it gets closer to the high vacuum region, so it takes time to exhaust and sufficient exhaust is not performed. It is not possible to obtain a final ultimate pressure. Further, there is a problem that sufficient cleanliness cannot be obtained. Therefore, when the gas cleaning of the processing chamber is performed, residual gas and particles may exist in the processing chamber.

Further, the vacuum pumping apparatus in which the turbo molecular pump (TMP) is combined with the dry pump (DRP) can maintain a high pumping performance in a high vacuum region, so that a sufficient ultimate pressure can be obtained and When cleaning is performed, residual gas and particles in the processing chamber can be exhausted sufficiently, but exhausting in a low vacuum region takes time and efficiency is poor.

The present invention has been made in view of the above circumstances, and shortens the exhaust time to improve the throughput, and also improves the final ultimate pressure to sufficiently eliminate the residual gas and particles in the processing chamber. It is intended to improve cleanliness.

[0007]

SUMMARY OF THE INVENTION The present invention is characterized in that a plurality of pumps having different exhaust characteristics are simultaneously driven and exhausted, and the simultaneous driving is suitable for each vacuum region. Since the pump mainly operates, the exhaust time can be shortened, the final ultimate pressure can be improved, and the cleanliness can be improved.
A control device for switching pumps is also unnecessary, and the device can be simplified.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

A first auxiliary exhaust pipe 5, a second auxiliary exhaust pipe 6, and a third auxiliary exhaust pipe 7 branched from a main exhaust pipe 8 on the side surface of the processing chamber 1.
Connect. The first auxiliary exhaust pipe 5 has a high vacuum region pump 4
The second auxiliary exhaust pipe 6 is provided with the pump 3 for the medium vacuum region, and the third auxiliary exhaust pipe 7 is provided with the pump 2 for the low vacuum region. Further, a dry pump (DRP) 9 is attached to the main exhaust pipe 8.
Is provided.

Further, as shown in FIG. 2, the pumping characteristics of the respective pumps are such that the pump 4 for the high vacuum region exhibits a maximum value of the pumping speed in the vicinity of the boundary between the low vacuum region and the medium vacuum region, and the performance gradually increases. Is reduced, but high exhaust performance is maintained up to a high vacuum range. or,
The evacuation performance of the pump 3 for the medium vacuum region remains almost unchanged until it reaches a maximum value after entering the medium vacuum region from the low vacuum region, but thereafter it drops sharply. Furthermore, the low vacuum region pump 2 has a high evacuation speed in the low vacuum region, but when it enters the middle vacuum region, the evacuation performance sharply decreases and the evacuation speed decreases.

The high vacuum region pump 4, the medium vacuum region pump 3, the low vacuum region pump 2 and the dry pump (DRP) 9 are simultaneously driven to evacuate the processing chamber 1. In the low vacuum region, the pump 2 for the low vacuum region mainly acts, and the pump 3 for the medium vacuum region and the pump 4 for the high vacuum region play an auxiliary role. In the medium vacuum region, the medium vacuum region pump 3 mainly acts, and the low vacuum region pump 2 and the high vacuum region pump 4 play an auxiliary role. Furthermore, in the high vacuum region, the high vacuum region pump 4 mainly acts, and the low vacuum region pump 2 and the medium vacuum region pump 3 play an auxiliary role. At least one of the high vacuum region pump 4, the medium vacuum region pump 3, and the low vacuum region pump 2 effectively operates in the entire vacuum region, and therefore, a sufficient final ultimate pressure is obtained. You can

As described above, by utilizing the characteristics of the high vacuum region pump 4, the medium vacuum region pump 3, and the low vacuum region pump 2, it is possible to shorten the exhaust time and improve the final ultimate pressure. Become. Further, since the three pumps are driven at the same time, it becomes unnecessary to switch the pumps and a control device for switching the pumps.

Although three pumps are used in the above embodiment, four or more pumps or two pumps having different exhaust characteristics may be used, and when three or more pumps are used, all of them are used. Instead of driving simultaneously, they may be driven in an appropriate combination.

[0014]

As described above, according to the present invention, pumps having different exhaust characteristics are simultaneously driven and exhausted, whereby switching of the pumps is not necessary, and a switching valve or a switching control device is provided. It is not necessary and the device can be simplified. Further, since the characteristics of each pump are utilized, excellent effects such as shortening of exhaust time, improvement of final ultimate pressure, and improvement of cleanliness of the processing chamber are exhibited.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a graph showing characteristics of the pump used in the embodiment.

[Explanation of symbols]

 1 Processing chamber 2 Pump for low vacuum region 3 Pump for medium vacuum region 4 Pump for high vacuum region 5 First auxiliary exhaust pipe 6 Second auxiliary exhaust pipe 7 Third auxiliary exhaust pipe 8 Main exhaust pipe 9 Dry pump (DRP)

Claims (1)

[Claims] 1. A vacuum evacuation device configuration, wherein a plurality of pumps having different evacuation characteristics are driven simultaneously for evacuation.